The present invention relates to an actuator device and is suitably applied to such as an AC (alternating current) servo motor.
Heretofore, in the AC servo motor, a rotor supported rotation-free and a stator consisting multiple stator iron-cores placed at predetermined intervals around said rotor and multiple coils wound around each stator-core are stored in one piece in the motor case.
Furthermore, in this AC servo motor, a rotation position sensor for detecting the rotation position of the axis of rotor (hereinafter referred to as rotor axis) is provided at the reversed rotation torque output side of the rotor axis outside of the motor case.
Then, in the actuator system utilizing such AC servo motor, a controller is provided in addition to the AC servo motor. And this controller executed various calculation processings for obtaining the desired rotation output in utilizing sensor signal to be put out from the rotation position sensor of the AC servo motor, and giving the driving current based on said calculation result from the controller to the AC servo motor, the controller controls the rotation of said AC servo motor.
However, in such actuator system, 3 wires for rotation driving coil and 4 to 12 wires for the rotation position sensor, totaling 7 to 15 comparatively large wires are required to connect between the controller and the AC servo motor as cable. Moreover, as the material of such wires, wirings having special cable specifications considering the effects of noise and break in cable caused by the mechanical vibration became necessary.
Furthermore, in such actuator system, since wirings between the controller and controllers of the upper ranks are necessary in addition to the wiring between the AC servo motor and said controller, wire cables become numerous and the construction of the system becomes complicated and its assembly task becomes worse.
Furthermore, in such actuator system, since the rotor and the rotation position sensor of the AC servo motor are placed apart, the rotor axis of the AC servo motor has to be thick in order that it can conduct the positioning efficiently and at high speed. And moreover, as the construction material of the coupling part, the material having high stiffness mechanically is required, it caused a problem that the system as a whole became heavy and large.
Furthermore, since in such actuator system, rotation position sensor is large and heavy, a large AC servo motor is required to conduct positioning at high speed and moreover, as its bearings high solidity bearing is required.
Furthermore, in such actuator system, the maximum value of the driving current to be given to the AC servo motor is limited due to heating of the AC servo motor while driving. However, in practice, since only low electric current containing a safety factor can be supplied to the AC servo motor, it caused a problem that the restriction is imposed on the output torque.
The present invention has been done considering the above points and is proposing an actuator device capable of simplifying the construction of actuator system and easily miniaturizing in improving its performance.
To obviate such problems according to the present invention, in the actuator device, the control means to control rotation of the rotor axis via the driving means is provided in the housing. As a result, in this actuator device, the number of wirings connected between the external devices can be remarkably decreased. Thus, an actuator device capable of simplifying the construction of actuator system can be realized.
Furthermore, according to the present invention, in the actuator device, the rotor axis rotation displacement detection means for detecting the rotation displacement of the rotor axis is provided in the housing. As a result, the rotation displacement of the rotor axis can be conducted with high precision and moreover, the positioning can be conducted efficiently and at high speed without increasing the size of the rotor axis and not using high solidity material as the material of said rotor axis. Thus, an actuator device capable of improving the performance and easily mini-sizing can be realized.
Furthermore, according to the present invention, we provide a rotor axis, a permanent magnet integrated concentrically with said rotor axis, the magnetic field generation means for generating the rotation power to the permanent magnet by generating magnetic field having the magnitude corresponding to the value of electric current of the driving current to be supplied, and a temperature sensor for detecting the temperature of the permanent magnet. As a result, in this actuator device, the actually acceptable upper limit of the current value of the driving electric current to be given to the coil can be easily detected based on the output of the temperature sensor. And thus, an actuator device capable of improving the performance can be realized.